Grate.



RfM. L C. G. SPRAGUE.

GRATB.

APPLIoATIoN FILED Mmm, 19,11.

1,089,682, Patented Mar. 10, 1914,

2 SHEETS-SHEET l.

@@z M im 2% cnLuMmA PMNwRArH co.. WASHINGTQN, D. c.

B.. M. & C. G. SPRAGUE.

GRATE.

APPLICATION FILED MAR. 27, 1911.

2 SHEETS-SHEET 2.

Patented Mar. 10, 1914.

" TED STATES PATENT UFFTCE.

ROBERT M. SPRAGUE AND CHARLES C. SPRAGUE, OF GOUNCIL BLUFFS, IOWA.

GRATE.

noeassa To all whomt' may concern.'

Be it known that we, ROBERT M. SrnAGUn and CHARLES C. SPRAGUE, citizens of the United States, residing at Council Bluffs, in the county of Pottawattamie and State of Iowa, have invented certain new and useful lmprovements in Grates, of which the following is a specification.

Our invention relates to improvements in furnace grates of the general type disclosed by Truesdell in his Patent No. 541,189, dated June 18, 1895, and has for its object to provide means which will render more effective and efficient the operation of said grates.

Tn the accompanying drawings, Figure 1- is a side elevation of the assembled grate. Fig. 2 is a top plan view. Fig. 3 is a transverse Vertical section along the line 3-3 of lfig. 4 facing with the arrows. Fig. 4l is a longitudinal vertical section along the line l of Fig. i2 facing with the arrow.

In general terms, our improved grate in its simplest form comprises a perimetrical frame 8 supported by suitable means as leg elements 9, and a set of movable grate bars 10, with controlling means for shaking the said bars periodically by hand and for normally locking the apparatus in rigid position. The frame may be of any suitable construction, but preferably consists of front and rear cross elements 11 and 12 attached to the ends of oppositely positioned side elements 13 and 14, said elements being arranged in rectangular form.

In case the grate is of large size, it is generally preferable to arrange the movable grate bars in several groups or sections separated by especially heavy grate bars attached rigidly to the front and rear members of the frame.

ln the embodiment here shown, as in Fig. 2, the movable bars are divided into only two groups, A and B, with a single rigid grate bar 15 between. In case a very large grate area is required, several groups may be used with a stationary bar such as 15, between adjacent groups, all being supported by a single grate frame.

Element 16 is the dead plate and parts 17, 18 and 19 are portions of the boiler or fire front. Said front is provided with suitable door openings, 20 and 21, preferably one Specification of Letters Patent.

Application filed March 27, 1911.

Patented Mar. 19, 191e.,

Serial No. 617,167.

for each set of bars to enable access to the under side of the grate and to facilitate removal of ashes. Provision is also made for attaching to the fire front, one or more brackets for mounting the shaking levers, and locks hereinafter described, one for each section of the grate,

All of the grate bars are preferably of a corrugated or zigzag shape including the intermediate or frame bars as shown in Fig. 2. These corrugations extend transversely of the bars. Moreover, the bars are all wedge shaped in cross section with the thin part 10 pointing downwardly as shown in Fig. 3. This general forni of construction is found to be well adapted, when the grate is shaken as hereinafter described, to crush and remove the clinhers that ordinarily form on a furnace grate.

The stationary bars,as 15, are constructed especially for strength and are made deep and solid with a thin central web portion 15 extending downwardly to serve both for strengthening the bar and for radiating heat transmitted thereto from the hot upper portion. The movable bars, on the other hand, are light composite structures which may be described as follows: The ends 2Q are solid, as are also two intermediate portions 23 where arms 24 extend downwardly and rest on the rocker-arms. rlhe main body of the bar, except at the solid portions aforesaid, is composed of vertical parallel web elements 25 spaced slightly apart and correspondingly corrugated in a transverse direction. The space between the two webs is substantially uniform as shown in Figs. 2 and 8. The cross section of each web is wedge-shaped, with the thin part extending downward as shown in Fig. This construction is particularly well adapted to insure thorough ventilation and cooling of the bars by means of supplying currents of air passing upward between the thin metallic webs of each bar as well as between the bars themselves, and thus preventing excessive heating of the grate.

Each set of grate bars is arranged so that in shaking, alternate bars will be raised and lowered respectively, at the same time. The

mechanism for thus operating the bars is constructed and arranged as follows: Transverse rock-shafts 26 are pivoted to depending lugs 27 and 2S respectively on the sides of the frame and on the intermediate rigid grate bar at the front and rear of the grate. These rocksshafts are provided on opposite sides wit-h laterally extending arms or loops 29. These arms are slightly hook-shaped and are turned upward at their outer enns. The arms or studs 24 on the lower sides of the movable grate bars are adapted to bear on these rockshaft arms. These arms 24 have tips 30 extending downward through the openings 29 in the said rock-shaft loops or arms 29, with means to fasten same in place as by pins 31 placed crosswise in the lower ends of said tips. Alternate bars rest on oppositely extending arms so that when the rock-shafts are oscillated, one bar will be raised, as the adjacent bar will be lowered. Then the mechanism is locked in its normal position with the grate bars in alinement, the shoulder 24 on the lower ends of the depending` arms of the bars rest uniformly in the hollows of the curved arms on the rock-shafts as shown in Fig. 1. 'Vhen the shafts are oscillated, the outer upwardly turned portions of the arms as they are moved upward tend more and more to engage the said shoulders on the lower ends of the arms 24, as shown in FiO. 4. The bars are thereby especially accelerated and given quick upward thrusts which tend to toss the clinkers somewhat and thereby more thoroughly shake and disintegrate them. This is particularly advantageous where the mass is badly caked as may result from the use of some kinds of coal or from improper firing. By reason of the fact that the arms 29 are upwardly curved or concave on their upper faces, said arms as they are alternately rocked upward tend to throw the bars longitudinally in opposite directions, thus producing a grinding or sawing action between the bars which assists to break up or crush any cinders that lodge between the bars. From an inspection of Fig. 2, it will be seen that spaces are provided between opposite ends of the bars and the respective ends of the grate frame, such spaces permitting the necessary longitudinal mo-vement of the bars as caused by the rock arms 29. In a fullsize grate these spaces are wide enough to permit sufficient longitudinal movement of the bars to effectthe desired result. The openings 29 in the arms 29 extend longitudinally of the arm for a con siderable distance, thus leaving the bar free to deviate somewhat from its regular motion in case it encounters an obstacle too hard for it to crush. Moreover, the pins 31 in the tips 30 are low enough to let the bar rise somewhat from its bearing on the arm 29 in case a substance too hard to crush gets caught between the bars.

In order that the two rock-shafts may readily be adjusted to operate in unison, the connecting link 32 is attached to the lower end of the pendent arms 33 rigidly iiXed to the rock-shafts. This link is pivoted at its ends to the lower ends of said arms and is provided with an adjustable joint 34 at an intermediate point with overlapping surfaces roughened or serrated so as to readily enable a definite adjustment. The said overlapping portions 35 and 36 are longitudinally slotted at 37 and 38 and bolts 39 are provided adapted to extend therethrough and adjustably fasten the overlapping ends together. This adjustable link 32 enables adjustment which will insure horizontal alinement of adjacent bars when they are locked in their normal position as shown in F ig. 1 and at A in Fig. 3. 1f the link 32 were too short or too long, the adjacent bars would be oppositely inclined, and the grate surface would be uneven. An adjacent link 40, adjustable at its rear end 40, is attached to the forward end 41 of this first said link and extends forward through an opening 17 in apron 17 to the corresponding shaking mechanism on the front of the grate. This mechanism at the front may be described as follows: A suitable bracket 42 is mounted on the front plate or apron 17 of the grate as above mentioned, one for each set of bars. There is pivoted to this bracket, an oscillatory lever element 43, to the lower end of which at 44 is pivoted the forwardly extending end of the second said link 40. This oscillatory element is provided with means for attaching a handle adapted to be operated by hand as will be described. There is also pivoted to the said bracket 42 a dog 45 adapted to engage the said oscillatory element 43 and normally lock it in a rigid position. The means for engaging the handle and the dog in the lever 43 preferably consist of two similar pockets 46 and 46, respectively, in the said oscillatory element but pointing in dierent directions. Thehandle is preferably adapted to be inserted in either one of these pockets, one of which preferably extends vertically and the other horizontally, so as to enable the handle to be operated in either a vertical or horizontal position, suiting the convenience of the operator. The dog 45 is provided with suitable means as a ring 48 for fastening it back out of engagement. The handle 47 is preferably curved at 47 near its lower end so as to cause the handle to stand erect when placed in its own socket 46 which is horizontal.

Ne claim as our invention:

1n a furnace grate, in combination, a frame, a pair of rock shafts supported thereby, a plurality of vertically movable grate bars supported transversely thereon, said rock-shafts having lateral arms rigidly attached thereto extending alternately in opcesses in the upper side of said arms, and

posite directions respectively, the upper face In testimony whereof We afX our signaof each of said arms having a concave recess tures in presence of two Witnesses.

therein said bars having downwardly eX- tending; rigid elements resting; in said resldable along the same to accelerate the up- Witnesses: Ward movement and means to oscllate said ALBERT B. SMITH, shafts 1n unison to shake said grate bars. WILLIAM J. LAUTERWAssER.

Gopiel of this patent may be obtained for ve cents each, by addressing the Commissioner o! Patenti, Waahingtoml). C. 

